1. Field of the Invention
The present invention relates generally to a UPnP (Universal Plug and Play) protocol, and more particularly to a method and an apparatus for giving a monopoly of a call in a UPnP telephony service for a call transmission/reception using the UPnP.
2. Description of the Related Art
In general, a home network is composed of an IP (Internet Protocol)-based private network. Such a home network connects and controls diverse devices, such as personal computers (PC), intelligent products, wireless devices, and the like, in a network through middleware to form a common virtual computing environment. Here, the middleware is configured to connect diverse devices in a peer-to-peer relationship to make the devices communicable with one another. Up to now, as the middleware, HAVI (Home AV Interoperability), UPnP (Universal Plug and Play), Jini (Java Intelligent Network Infrastructure), HWW (Home Wide Web), and the like, have been utilized.
In the computing environment constructed using the UPnP middleware, the respective devices are allocated with addresses from a server according to a DHCP (Dynamic Host Configuration Protocol) or addresses selected by auto IP (Internet Protocol) designation function (auto IP), and perform communication with one another and a search/inquiry on a network through the allocated addresses.
The UPnP network is a home network technology that is most commonly used at present, and defines a UPnP device, a UPnP service, and a protocol between them. The UPnP network is composed of controlled devices (CD) that are home network devices connected to and controlled by an IP-based home network, and control points (CP) that are devices controlling the controlled devices. The control point, which is a device that performs the control of the controlled devices, requests an event from a controlled device, and receives the event from the controlled device. The controlled device is a device that performs a determined function according to the request of the control point. If a state is changed, the controlled device transmits the requested event to the control point that has requested the event.
The UPnP network devices as configured above perform processes such as advertisement, discovery, description, control and eventing.
The advertisement process is a process in which a new controlled device is connected to the home network and informs other devices on the home network of itself.
The discovery process is a process in which a new control point is connected to the home network and searches for the controlled devices that operate on the home network.
The description process is a process in which the control point grasps the function of a newly added device by parsing a service description XML (Extensible Markup Language) file or a device description XML file through an IP address of the searched controlled device in order to control the controlled device.
The control process is a process in which the control point, when intending to provide a specified service through the controlled device, transmits a control message (action request) for requesting a predetermined service to the corresponding controlled device using a SOAP (Simple Object Access Protocol) according to a UPnP device architecture, and receives a response message (result, variable value) to the control message.
The eventing process is a process in which the information change state of the controlled device that has provided the predetermined service is confirmed according to a control command transmitted from the control point.
At present, in a UPnP telephony WC (Working Committees), the standard for controlling equipment having a telephony function by using equipment that does not have the telephony function in a home network based on the UPnP technology and making it possible to make a call using the equipment has been established. At present, UPnP does not provide appropriate security with respect to a call, and thus even if a specified user makes a phone call, a certain user can disconnect the call or tap a telephone wire.
In order to solve this problem, the UPnP telephony intends to adopt a Device Protection (DP) standard of which the standardization has now been performed in 1 security TF (Task Force) of the UPnP IGD (Internet Gateway Device) WC. However, since the device production is basically prepared on the basis of the IGD, it is difficult to solve the problems handled in the telephony service.
The UPnP device protection provides the security for the device through the following processes. First, a role that can call an action for each action is defined for each DCP (Device Control Protocol), and the UPnP equipment that implements the device protection service can determine whether to perform an action with reference to a mapping table when a request for executing the action is input from the CP.
Then, all the CPs that have not been authenticated have public authority. If the CP finds the DP service, it performs an introduction process, and the device authenticates the DP.
Then, the device can give a role to each CP, and if necessary, can additionally perform a user authentication, and a user can also receive the role.
Using the table, the CP can call the action having the use authority, and the service confirms the call authority and performs the action.
However, this technique has the following problems. First, the telephony service does not appropriately give the role to the respective devices. If the device has the role, another user may unintentionally end a call or shift a call session using a device having a manager role while a user makes the call. In general, the call belongs to the user who has initially set the call, and it is the user's own authority, which started the call, to end the call or to shift a session. Accordingly, the authority of the call user may be infringed due to the giving of the role to the device.
Second, the DP is basically prepared on the basis of the IGD, and executable actions and non-executable actions are clearly discriminated. In the case of a gateway, an action that can affect the system exists, and it is necessary that only a manager can call the action. However, the telephony does not have such clear discrimination. This is because, even if the authority of a specified user is weak, it is impossible to make the specified user not shift the call session or not ring off the call. Accordingly, the user can perform all the actions, and it is not appropriate for the telephony to determine the authority by actions.
Accordingly, there is a need for a scheme capable of protecting the call user's authority that is appropriate to the telephony service using UPnP.